Thin film lithium conducting powder material deposition from flux

ABSTRACT

The present invention is directed to battery technologies and processing techniques thereof. In various embodiments, ceramic electrolyte powder material (or component thereof) is mixed with two or more flux to form a fluxed powder material. The fluxed powder material is shaped and heated again at a temperature less than 1100° C. to form a dense lithium conducting material. There are other variations and embodiments as well.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/749,496, filed 7 Jan. 2013, entitled “THIN FILM LITHIUMCONDUCTING POWDER MATERIAL DEPOSITION FROM FLUX”, which in incorporatedby reference herein for all purposes.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

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REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAMLISTING APPENDIX SUBMITTED ON A COMPACT DISK

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BACKGROUND OF THE INVENTION

The present invention is directed to battery technologies and processingtechniques thereof.

In the recent years, with shortage of fossil-fuel based energy andadverse environmental effects from the consumption of fossil fuels, bothpublic and private sectors have poured much valuable resources intoclean technologies. An important aspect of clean technologies is energystorage, and in particular, battery systems. In the past, many batterytypes have been developed and used, each with their respectiveadvantages and disadvantages. For its chemical properties, includinghigh charge density, lithium based batteries have become the leadingbattery technology for mobile energy storage applications. In arechargeable lithium-ion battery, lithium ions move from the negativeelectrode to the positive electrode during discharge through a liquidelectrolyte. For safety reasons in various applications, it is desirableto replace the liquid component and develop an all solid state lithiumion battery. All solid state lithium ion batteries would have manyapplications in the clean technology sector, such as battery system forelectric cars, energy storage for solar cells, and many others.

Unfortunately, contemporary battery systems have been inadequate andhigh volume manufacturing processes for solid state batteries are notwell developed. Therefore, it is desirable to have new battery systemsand develop new techniques for manufacturing of batteries.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to battery technologies and processingtechniques thereof. In various embodiments, ceramic electrolyte powdermaterial (or component thereof) is mixed with two or more flux materialsat a temperature of less than 400° C. to form a fluxed powder material.The fluxed powder material is shaped and heated again at a temperatureless than 1100° C. to form a dense lithium conducting material. Thereare other variations and embodiments as well.

According to an embodiment, the present invention provides a method fordepositing lithium conducting electrolyte materials including those withthe garnet, perovskite, NASICON and LISICON structures. The methodincludes providing a lithium conducting ceramic powder material at afirst quantity. The ceramic powder material is characterized by a firstdensity. The lithium conducting ceramic powder material has a medianparticle size of about 100 nm to 10 um. The method also includesproviding a first flux material at a second quantity, which is less than51% of the first quantity. The first flux material comprises lithiummaterial. The first flux material has a melting temperature of about500-1000° C. The method also includes providing a second flux materialat a third quantity. The second flux material is characterized by amelting temperature of about 500-1000° C. The method further comprisesmixing at least the first flux material and the second flux material toform a eutectic mixture, which is characterized by a melting point ofless than 1000° C. . The method also includes subjecting the eutecticmixture a temperature of about 100 to 1000° C. Additionally, the methodfurther includes mixing the eutectic mixture with the ceramic powdermaterial to form a fluxed ceramic powder material. The methodadditionally includes shaping the fluxed ceramic powder material to apredetermined shape. The method also includes heating the shaped fluxedceramic powder material to a temperature of less than 1100° C. Moreover,the method includes forming a dense lithium conducting material, thedense lithium conducting material being characterized by a seconddensity, the second density is at least 80% of the theoreticalcrystalline density of the material.

It is to be appreciated that embodiments of the present inventionprovides numerous advantages over conventional techniques. The solidelectrolyte is manufactured at a relatively low (compared to existingtechniques) temperature and may be deposited upon a substrate. The lowtemperature growth and/or deposition translate to low manufacturing costand high efficiency. In addition, since the solid electrolyte materialcan be deposited as a thin film onto current structure elements ofbatteries, the solid electrolyte manufacturing according to embodimentsof the present invention can be readily and conveniently incorporatedinto battery cell designs. In addition, solid electrolytes according toembodiments of the present invention can have high stability to water,air, lithium metal anodes, and with cathode potentials of greater than5V.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram illustrating a process for flux growth ofa thin film electrolyte ceramic according to embodiments of the presentinvention.

FIG. 2 is a simplified diagram illustrating a process of flux sinteringof ceramic electrolyte thin film according to embodiments of the presentinvention.

FIG. 3 is a simplified diagram illustrating a two-component batterystructure utilizing the solid electrolyte and substrate manufacturedusing processes according to embodiments of the present invention.

FIG. 4 is a simplified diagram illustrating a one-component batterystructure utilizing the solid electrolyte and substrate manufacturedusing processes according to embodiments of the present invention.

FIG. 5 is a simplified diagram illustrating a process of depositingmixed flux and powder material onto a sheet of substrate according to anembodiment of the invention.

FIG. 6 is a simplified diagram illustrating a process of dipping asubstrate into a mixed flux and powder material according to anembodiment of the invention.

FIG. 7 is a simplified diagram illustrating a slot casting process fordepositing electrolyte mixture material on a substrate according to anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to battery technologies and processingtechniques thereof In various embodiments, a ceramic electrolyte powdermaterial (or components thereof) is mixed with one or more fluxmaterials to form a fluxed powder material. The fluxed powder materialis shaped and heated at a temperature less than 1000° C. to form a denselithium conducting material. There are other variations and embodimentsas well.

As explained above, existing batteries and manufacturing processesthereof are inadequate for current uses. Batteries with liquidelectrolytes have the problem of forming SEI layers that limit cyclelife. In addition, they do not allow safe usage of Li metal anodes,thereby reducing energy density. In addition, batteries with liquidelectrolytes are hazardous, as they are a hydrocarbon that can burn.

Similarly, batteries with polymer electrolytes have many disadvantagesas well.

Polymer electrolytes form SEI layers, which limit cycle life. Inadditional, they cannot be reliably deposited at less than 50 μmthickness, which translate to low energy density. Also, batteries withpolymer electrolytes do not have sufficient Li⁺ conductivity at <60 ° C.

LiPON type of batteries similarly has is disadvantages. Among otherthings, LiPON type of batteries is characterized by low Li+ conductivityat reasonable temperatures. In addition, during the manufacturingprocess, the electrolyte material is typically deposited by expensivePVD processes.

Various types of solid electrolytes have their respective disadvantages.For example, sulfide solid electrolytes are unstable to air, water,and/or Li anodes. Also, sulfide solid electrolytes typically cannot bedeposited as thin films. Many oxide solid electrolytes, on the otherhand, have low Li⁺ conductivity at reasonable temperatures, renderingthem unsuitable. The Lithium Garnet materials are a notable exception.

It is therefore to be appreciated that embodiments of the presentinvention provide advantages over existing materials and manufacturingprocesses thereof. As explained above, lithium ion batteries are veryuseful in many applications. Solid state lithium conducting ceramicmaterials are of immense technological importance for the development ofall solid state lithium ion batteries. In various applications, aconducting ceramic forms the electrolyte component in the battery. Forexample, the conducting ceramic separates the positive and negativeelectrodes (i.e., the cathode and the anode). The electrolyte needs to(1) provide a medium for fast transport of lithium ions, and (2) preventany electronic flow between the electrodes, as an electronic flowbetween the electrodes can short-circuit the battery and causeself-discharge. When assembled in the solid state battery, the ceramicelectrolyte needs to have sufficiently low ionic resistance that it doesnot present a limiting factor to high current flow. The ionic resistancevalue is inversely proportional to both the ionic conductivity and thethickness of the electrolyte layer. It is therefore desirable for theceramic electrolyte to (1) have high conductivity, and (2) be capable ofbeing fabricated in a thin-film geometry. Currently, there are no knownsolid Li ion conductors with conductivity >1e-5S/cm that can bedeposited at scale in thin film form. The ability to do so would allowfor safe use of lithium metal anodes, which make for batteries withhigher energy density.

Lithium conductive electrolytes often have low conductivity or lowstability. Lithium garnets are known to have relatively good chemical,thermal, and electrochemical stability; when doped to retain the cubicphase at low temperature, garnets may have high conductivity.Compositions similar to Li₇La₃Zr₂O₁₂ and doped compositions such asLi_(7-x)La₃Zr_(2-x)M_(x)O₁₂, where M can be Nb or Ta, orLi_(7-x)Al_(y)La_(3-y)Zr₂O₁₂ have high conductivity. However, methodsfor depositing garnet as thin films are generally unavailable, whichlimits garnets' practical use. Lithium conducting ceramic materials thatcan be used as electrolytes in solid state batteries include materialsfrom the garnet family, perovskites, and tungsten bronzes. For example,garnet-type Li₅LaNb₂O₁₂ typically has a lithium-ion conductivity ofabout 10⁻⁵ Scm⁻¹. Similar lithium conducting ceramic materials includethose with the NASICON structure and the LISICON structure. It is to beappreciated that embodiments of the present invention disclose a methodof depositing a thin film of lithium conducting garnetLi_(A)La_(B)M′_(C)M″_(D)Zr_(E)O_(F), where 4<A<8.5, 1.5<B<4, 0≤C<2,0<D<2, 0<E<2, 10<F<14 and M′is selected from Al, Mo, W, Nb,Sb, Ca, Ba,Sr, Ce, Hf, Rb, and Ta, and M″ is selected from Al, Mo, W, Nb, Sb, Ca,Ba, Sr, Ce, Hf, Rb, and Ta. Other compositions such asLi_(A)La_(B)M′_(C)M″_(D)Ta_(E)O_(F), Li_(A)La_(B)M′_(C)M″_(D)Nb_(E)O_(F)are included as well.

A common feature of lithium conducting ceramic materials is that theyare traditionally prepared by solid state reaction processes, where thecrystalline structure is synthesized by mixing the components in theform of oxides, carbonates, nitrates, acetates, hydroxides or otherinorganic salts followed by repeated calcination at a high reactiontemperatures typically greater than 800° C. and for a period of time(e.g., typically >6 hours). The high temperature process is needed toform the correct crystalline phase, and it is often difficult to formdesired crystalline structure using solid state reaction method. Inaddition, the repeated solid state reactions are often too expensive andinefficient for commercialization of the product. Furthermore, in thecase of Garnets the calcined product usually requires even highertemperatures (>1000° C.) for long times (>20 hrs) for the purposes ofsintering (i.e., to heat the powdered material so that it forms a densepolycrystalline ceramic). The requirement of such high processingtemperatures to achieve the required phase and to form it into a densestructure presents significant complications for integrating suchmaterials into a thin film battery design where the electrolyte may needto be co-processed with the other elements of the battery (e.g., currentcollectors, anode and cathode).

Various embodiments of the present invention provide a techniques whichin one step achieve both (1) the synthesis of the correct phase and (2)forming it into a thin film geometry. It is to be appreciated that thetechniques and processes according to embodiments of the presentinvention significantly reduce processing temperatures compared toconventional techniques.

FIG. 1 is a simplified diagram illustrating a process for flux growth ofa thin film electrolyte ceramic according to embodiments of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications. To prepare aflux-grown lithium conducting thin film electrolyte, a slurry is firstprepared. For example, the slurry comprises a mixture of electrolyte andflux powders. Depending on the application, the electrolyte powders aretypically powdered oxides, carbonates, nitrates, sulfates and/or otherinorganic salts of the principal electrolyte elements. In a specificembodiment, the electrolyte comprises a garnet material with the formulaLi_(7-x)La₃Zr_(2-x)M_(x)O₁₂, and the viable powdered oxide componentscomprise LiOH, La₂O₃, and ZrO₂. Depending on the material, theelectrolyte powder material can have a median particle size of about 100nm to 10 um. In a specific embodiment, the electrolyte powder materialis characterized by a median particle size of about 100 nm to 2 um.

The additional powders of the flux component(s), which comprisesinorganic salts of lithium (or other alkali metals), are added to theelectrolyte powders. Depending on the application, such salts mayinclude LiOH, Li₂CO₃, Li₃BO₃, LiCl, LiBr, and/or LiI. Flux material canbe alkali metal hydroxides, chlorides, nitrates, sulphates, and/orothers. In various embodiments, the flux comprises two types of fluxpowders. For example, the first flux material comprises one or morematerials selected from LiOH, LiCl, LiBr, LiNO₃, and LiSO₄, and thesecond flux material comprises one or more materials selected from NaOH,NaCl, NaNO₃, NaSO₄, NaBr, and Na₂CO₃. In various embodiments, three ormore different types of flux materials are used. For example, a thirdflux material comprising KOH, KCl, KNO₃, KSO₄, KBr, and/or K₂CO can beused.

Typically, individual flux materials are characterized by a meltingpoint of about 700° C. By mixing two flux materials which posess aEutectic melting point, a lower melting temperature can be achieved, andthe Eutectic temperature can be about 200˜400° C. For example, two fluxpowders can be used together to form a Eutectic solvent mixture:

0.3 LiOH−0.7 NaOH(m.p.=251° C.)

0.29LiOH−0.71 KOH(m.p.=227° C.)

The electrolyte components and flux powders are mixed together. In theflux growth method the flux makes up the majority of the volume. Theratio of flux powder to electrolyte powders can be about 2:1, 3:1, 6:1,or other ratios. It is to be appreciated that electrolyte powders andflux powers can be mixed using various types of processes, such as ballmilling in an inert liquid, which can be ethanol, isopropanol, toluene,and/or others.

Subsequently, the mixture of electrolyte and flux powders is cast onto acarrier substrate. For example, for the purposes of making a solid statebattery, the substrate can be used to serve as the anode currentcollector of an assembled battery. It is to be appreciated that for thisapplication, a thin conductive material is used. In various embodiments,the carrier substrate comprises a copper, nickel, or stainless steelfoil of <25 um thickness. In certain embodiments, the carrier substratecomprises polymer material with nickel and/or copper coating. Thesubstrate can be other materials, such as nickel, as well.

As shown in FIG. 1, electrolyte powders (1 a) is mixed with flux powders(1 b) and provided on the carrier substrate (1 c).

In various embodiments, the flux materials are chosen to have lowmelting points. Additionally, flux material may include multiple fluxcomponents, which together form eutectic mixtures that exhibit evenlower melting point than the components by themselves. The flux materialis heated up to a temperature higher than its melting point, and underthis temperature it forms a liquid phase. In its liquid phase, the fluxfills the space between the powders of the ceramic electrolyte asillustrated in (2) of FIG. 1.

The components of the ceramic electrolyte are soluble in the liquidflux, and therefore dissolves in the liquid flux. For example, thedissolved ceramic electrolyte powers can form, with the liquid fluxmaterial, a completely molten layer on the substrate as illustrated in(3) of FIG. 1.

As shown in (4) of FIG. 1, the nucleation process of the desiredelectrolyte phases occurs. In an embodiment, the nucleation process canbe initiated by gently cooling the system.

Under the nucleation process, the crystallites of electrolyte continuesto grow and coalesce, thereby forming a continuous layer on thesubstrate. Also during this process, the excess molten flux (5 b) ispushed out from the space the dense and shaped electrolyte material (5a). As shown in (5) of FIG. 1, molten flux (5 b) overlays the formedelectrolyte material (5 a), and during this process, the electrolytematerial is densified, as the space that previously existed among theelectrolyte powder particles is removed.

As explained above, flux material is used to facilitate the formation ofdense and shaped electrolyte material, and therefore the flux materialis to be removed. When sufficient film growth has been achieved, thesystem is quenched to room temperature and the excess flux is washedaway using a solvent. For example, the solvent may comprise water,ethanol, isopropanol, acetone, and/or acetonitrile. The solvent removesthe flux material without removing the shaped electrolyte material.Depending on the application, the solvent can be H₂O, ethanol ,acetone,and/or other types of material. The flux may be chemically etched byacids such as HCl, or bases such as NH₄OH, or other types of etchants.As shown in (6) of FIG. 1, after removing the flux material, acontinuous dense polycrystalline ceramic layer remains on the carriersubstrate. The thickness of the ceramic layer is between about 100 nmand 100 um and more preferably 1-10 um. The performance of the ceramicelectrolyte is as good as (or better) than bulk ceramic materialprepared by conventional methods. An advantage of the present growthmethod is that it may generate a structure with few grain boundaries inthe plane of the film which would otherwise cause a reduction in thetotal conductivity.

It is to be appreciated that depending on the application, one or moresteps described above can be added, removed, replaced, modified,rearranged, and/or overlapped, which should not limit the scope of theclaims.

FIG. 2 is a simplified diagram illustrating a process of flux sinteringof ceramic electrolyte thin film according to embodiments of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications.

It is to be appreciated that depending on the processes and materials,film growth from a completely molten phase may result in unevenmicrostructures due to abnormal grain growth, where preferentialcrystallite grows along favorable crystallographic directions ornucleation of secondary phases. Therefore, for certain situations, it isdesirable to use pre-synthesized electrolyte powders in the slurry inplace of the raw components. Depending on the application, theelectrolyte compoment powders are typically powdered oxides, carbonates,nitrates, sulfates and/or other inorganic salts of the principalelectrolyte elements. In a specific embodiment, the electrolytecomprises a garnet material with the formulaLi_(A)La_(B)M′_(c)M″_(D)Zr_(E)O_(F), and the viable powdered oxidecomponents comprise Li₂CO₃, La₂O₃, and ZrO₂. In various embodiments,pre-synthesized electrolyte ceramic powders are prepared by conventionalhigh temperature reaction between the components followed by milling toreduce particle size to around 1 micron. For example, 100 gms ofpre-synthesized Li₇La₃Zr₂O₁₂ electrolyte powder can be prepared bymixing 31.03 gms of Li₂CO₃, 58.65 of La₂O₃, and 29.57 gms of ZrO₂ byball milling in isopropanol for 24 hrs. The dried mixture is thencalcined at 900° C. for 12 hrs, and then 1100° C. for 12 hrs to form thegarnet phase. The calcined powder is then re-milled in isopropanol toreduce the average particle size to 12 um.

The synthesized electrolyte powder material is mixed with the fluxcomponents and mixed with an appropriate liquid to form a slurry forfilm casting, which is similar to the process illustrated in FIG. 1. Theslurry is cast onto a substrate to form a film of thickness between 200nm-100 um. As described above, the substrate can be a metal conductivematerial. As shown in (1) of FIG. 2, pre-synthesized electrolyte powder201 is mixed with flux material 202, and the mixture of the two areprovided on the substrate 203. The flux material 202 is characterized bya much small powder size compared to the pre-synthesized electrolytepowder material 201, thereby allowing the flux material 202 to fill intothe space between the pre-synthesized electrolyte powder material 201.

The dried slurry is heated to initiate melting of the flux components.For example the mixture can be heated at a rate of 1° C./min to atemperature of 400° C. and held at this termperature for 6 hrs. Invarious embodiments, the flux material 202 is provided at a lower volumefraction relative to the pre-synthesized electrolyte powder material201. As a result of the smaller volume fraction of the fluxat themelting temperature of flux components, the moltenflux material 202cannot completely dissolve the pre-synthesized electrolyte powdermaterial 201.

As shown in (2) of FIG. 2, the liquid flux 202A (formed by the meltedflux material 202) initially wets the particles of the pre-synthesizedelectrolyte powder material 201 and filling into the space among theseparticles. As shown in (3) of FIG. 2, the viscous forces causerearrangement of the pre-synthesized electrolyte powder material, whichresults in increased packing efficiency and densification. For example,the densification can result in a reduction in volume of as much as5-20%.

With the help of viscous forces, liquid phase sintering occurs, wherethe ceramic electrolyte particles are dissolved at high energy contactpoints and re-precipitated at lower energy vertices, thereby resultingin further densification and coarsening of the ceramic microstructure asshown in (4)-(6) of FIG. 2. As shown in (4) of FIG. 2, electrolytematerial 201A is being reshaped. The electrolyte material forms apolycrystalline film 201B deposited on the substrate 203, as shown in(6) of FIG. 2. Excess flux material is expelled to the surface of thefilm 201B. Depending on the application, the excess flux material can beremoved in many ways. For example, the excess flux material is washedaway. In certain embodiments, certain amount of flux material is trappedat triple points within the ceramic structure, where it has minimaland/or insignificant effect on the transport properties of theelectrolyte 201B.

FIG. 3 is a simplified diagram illustrating a two-component batterystructure utilizing the solid electrolyte and substrate manufacturedusing processes according to embodiments of the present invention. Thisdiagram is merely an example, which should not unduly limit the scope ofthe claims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. In FIG. 3, a battery cell300 has a two-component architecture. Cathode particle elements 301 and303 are coated on both sides of a cathode current collector 302. Forexample the cathode material may comprise a mixture of an active cathodematerial LiFePO₄ and conductive additive materials such as carbon blackfor electronic conductivity and presynthesized Li₇La₃Zr₂O₁₂ material forionic conductivity. The thickness of the cathode layers 301 and 303 arebetween 1 um and 1000 um, preferably 100 um. The thickness of thecathode current collector element, 302 is preferably less than 20 um.Anode current collector 305 is coated on both sides by electrolyteelements 304 and 306.

In an embodiment, the garnet precursor material, the flux material, andoptionally a solvent, dispersant, and/or binder may be coated onto asubstrate such as a nickel, copper, or stainless steel foil. The coatingcan be done by screen printing, slot-die, gravure, microgravure, doctorblade, knife-over-roll, comma coating, reverse comma coating, and/orother techniques. The coating may be done on one or both sides of thesubstrate. The coating is dried, calendered, and sintered to produce adense garnet film on one or both sides of the substrate. This componentmay be married with a cathode to produce a battery.

FIG. 4 is a simplified diagram illustrating a one-component batterystructure utilizing the solid electrolyte and substrate manufacturedusing processes according to embodiments of the present invention. Thisdiagram is merely an example, which should not unduly limit the scope ofthe claims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. In FIG. 4, the cathodecurrent collector 403 is positioned between cathode particle elements402 and 404. The cathode element 402 interfaces with the electrolyte401. The cathode element 404 interfaces with the electrolyte 405.

In addition to directly depositing electrolyte powder material and fluxmaterial onto a conductive surface, the mixed flux and electrolytepowder material can also be deposited onto surfaces of substrates aftermixing. FIG. 5 is a simplified diagram illustrating a process ofdepositing mixed flux and powder material onto a sheet of substrateaccording to an embodiment of the invention. This diagram is merely anexample, which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. As shown in FIG. 5, a molten mixture 504 is provided.The molten mixture 504 comprises one or more flux material and theelectrolyte powder material in molten state. A substrate 503 is s sheetof substrate material. For example, the substrate 503 is a sheet ofconductive current collector material that is transported into themolten mixture by rollers 501 and 502, which parts of a transportsystem. The portion of the substrate 503 submerged in the molten mixture504 is coated with the molten mixture. Once cooled and formed, the fluxportion of the molten mixture 504 is removed from the surface of thesubstrate 503, thereby leaving a layer of electrolyte material on thesubstrate surface. It is to be appreciated that this process oftransporting a large sheet of substrate allows fast manufacturing ofbattery subcomponents and is compatible with existing manufacturingprocesses and tools thereof.

FIG. 6 is a simplified diagram illustrating a process of dipping asubstrate into a mixed flux and powder material according to anembodiment of the invention. This diagram is merely an example, whichshould not unduly limit the scope of the claims. One of ordinary skillin the art would recognize many variations, alternatives, andmodifications. As shown in FIG. 6, a molten mixture 601 is provided. Themolten mixture 601 comprises one or more flux material and theelectrolyte powder material in molten state. A substrate 602 is s sheetof substrate material. Flux and electrolyte powder materials aredeposited onto the substrate 602 when the substrate 602 is dipped intothe molten mixture 601. For example, since both sides of the substrate602 are dipped into the molten mixture 601, the molten mixture 601 isdeposited on both sides of the substrate 602. Once the molten materialis cooled, the flux material can be removed, leaving a layer ofelectrolyte powder material deposited on the substrate.

FIG. 7 is a simplified diagram illustrating a slot casting process fordepositing electrolyte mixture material on a substrate according to anembodiment of the present invention. This diagram is merely an example,which should not unduly limit the scope of the claims. One of ordinaryskill in the art would recognize many variations, alternatives, andmodifications. As shown in FIG. 7, an electrolyte mixture 701 isprovided within the cavity of a slot-casting apparatus 702. Theelectrolyte mixture 701 comprises dense electrolyte material andoptionally includes a polymer material. The dense electrolyte materialis formed by mixing electrolyte powder material with flux material, andlater removing the flux material to have dense electrolyte material incrystallite form. The polymer material is mixed with the denseelectrolyte material to provide structure support and improved density.For example, the polymer material can be PVDF, PVDF-HFP, PAN, PEO,and/or other types of stable polymer material. In various embodiments,the polymer material is stable at about 0-4.5V versus lithium. Throughthe slot-casting apparatus 702, an electrolyte mixture layer 703 isdeposited on the substrate 704. For example, the substrate 704 is acurrent collector element of a battery. It is to be appreciated that byusing the slot-casting process, it is possible to deposit theelectrolyte mixture material onto a large sheet of substrate, which canlater be partitioned to form current collector elements of batteries.

The following description is presented to enable one of ordinary skillin the art to make and use the invention and to incorporate it in thecontext of particular applications. Various modifications, as well as avariety of uses in different applications will be readily apparent tothose skilled in the art, and the general principles defined herein maybe applied to a wide range of embodiments. Thus, the present inventionis not intended to be limited to the embodiments presented, but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

In the following detailed description, numerous specific details are setforth in order to provide a more thorough understanding of the presentinvention. However, it will be apparent to one skilled in the art thatthe present invention may be practiced without necessarily being limitedto these specific details. In other instances, well-known structures anddevices are shown in block diagram form, rather than in detail, in orderto avoid obscuring the present invention.

The reader's attention is directed to all papers and documents which arefiled concurrently with this specification and which are open to publicinspection with this specification, and the contents of all such papersand documents are incorporated herein by reference. All the featuresdisclosed in this specification, (including any accompanying claims,abstract, and drawings) may be replaced by alternative features servingthe same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

Furthermore, any element in a claim that does not explicitly state“means for” performing a specified function, or “step for” performing aspecific function, is not to be interpreted as a “means” or “step”clause as specified in 35 U.S.C. Section 112, Paragraph 6. Inparticular, the use of “step of” or “act of” in the Claims herein is notintended to invoke the provisions of 35 U.S.C. 112, Paragraph 6.

Please note, if used, the labels left, right, front, back, top, bottom,forward, reverse, clockwise and counter clockwise have been used forconvenience purposes only and are not intended to imply any particularfixed direction. Instead, they are used to reflect relative locationsand/or directions between various portions of an object.

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. Therefore, the above description and illustrations should not betaken as limiting the scope of the present invention which is defined bythe appended claims.

1. A method for material, the method comprising: providing a lithiumconducting ceramic powder material at a first quantity, the ceramicpowder material being characterized by a first density, the lithiumconducting ceramic powder material being characterized by a medianparticle size of about 100 nm to 10 μm; providing a first flux materialat a second quantity, the second quantity being less than 51% of thefirst quantity, the first flux material comprising lithium material, thefirst flux material being characterized by a melting temperature ofabout 500-1000° C.; providing a second flux material at a thirdquantity, the second flux material being characterized by a meltingtemperature of about 500-1000° C.; mixing at least the first fluxmaterial and the second flux material to form a eutectic mixture, theeutectic mixture being characterized by a melting point of less than800° C.; subjecting the eutectic mixture a temperature of about 100 to1100° C. ; mixing the eutectic mixture with the ceramic powder materialto form a fluxed ceramic powder material; shaping the fluxed ceramicpowder material in to a predetermine shape; flux sintering the shapedfluxed ceramic powder material; and forming a dense lithium conductingmaterial, the dense lithium conducting material being characterized by asecond density, the second density is at least 20% higher than the firstdensity.
 2. The method of claim 1 wherein the lithium conducting ceramicpowder material comprises electrolyte component powders selected fromone or more of metal oxides, nitrates, carbonates, sulfates, borates,and hydroxides.
 3. The method claim 2 wherein electrolyte componentpowders is characterized a quantity less than the second quantity. 4.The method of claim 1 wherein the first flux material comprisesinorganic salts of lithium material.
 5. The method of claim furthercomprising providing a substrate material, the substrate having ametallic surface.
 6. The method of claim 1 wherein the second density isat least 40% higher than the first density.
 7. The method of claim 1further comprising melting the lithium conducting ceramic powdermaterial by the eutectic mixture at a temperature of less than 800° C.8. The method of claim 1 further comprising dissolving the lithiumconducting ceramic powder material by the eutectic mixture at atemperature of less than 800° C.
 9. The method of claim 1 wherein theeutectic material comprises less than 80% of a total mass of the fluxedceramic powder material.
 10. The method of claim 1 wherein thepredetermined shape is disc, sheet, cylinder, or pellet.
 11. The methodof claim 1 wherein the second quantity being about 15-30% of the firstquantity.
 12. The method of claim 1 wherein the first flux materialcomprises one or more materials selected from LiOH, LiCl, LiBr, LiNO₃,Li₃BO₃ and LiSO₄.
 13. The method of claim 1 wherein the second fluxmaterial comprises one or more materials selected from NaOH, NaCl,NaNO₃, NaSO₄, NaBr, and Na₂CO₃.
 14. The method of claim 1 wherein theeutectic mixture is characterized by a melting point of about 200 to800° C.
 15. The method of claim 1 further comprising subjecting the fluxmaterial to a temperature of about 200 to 1000° C.
 16. The method ofclaim 1 wherein the lithium conducting ceramic powder material beingcharacterized by a median particle size of about 100 nm to 2 um.
 17. Themethod of claim 1 wherein the lithium conducting ceramic powder materialcomprises a garnet material.
 18. The method of claim 1 wherein thelithium conducting ceramic powder material comprises a perovskitematerial.
 19. The method of claim 1 wherein the lithium conductingceramic powder material comprises Nasicon material, Lisicon material,and/or a Tungsten Bronze material.
 20. The method of claim 1 wherein thesubstrate comprises a polymer material and a metal surface overlayingthe polymer material.
 21. The method of claim 1 further comprisingproviding a third flux material at a third quantity, the third fluxmaterial comprising KOH, KCl, KNO₃, KSO₄, KBr, and/or K₂CO.
 22. Themethod of claim 1 further comprising removing the first flux materialand the second flux material by subjecting the dense lithium conductingmaterial to one or more solvent washings, the one or more solventcomprising water, ethanol, isopropanol, acetone, acetonitrile, an acid,and/or a base.
 23. The method of claim 1 wherein the dense lithiumconducting material is deposited on a metal conductive material.
 24. Themethod of claim 1 further comprising: providing a substrate material,the substrate material comprises a layer of metal conductive material,wherein the lithium conducting ceramic powder material is provided onthe layer of metal conductive material.
 25. A method for depositingmaterial, the method comprising: providing components of lithiumconducting ceramic powder material at a first quantity, the componentsbeing characterized by a first density, the components beingcharacterized by a median particle size of about 100 nm to 10 μm;providing a first flux material at a second quantity, the first fluxmaterial comprising inorganic salts of lithium material, the first fluxmaterial being characterized by melting temperature of about 500-1000°C.; providing a second flux material at a third quantity, the secondflux material being characterized by melting temperature of about500-1000° C.; mixing the first flux material and the second fluxmaterial with the components to form the fluxed ceramic powder material;shaping the fluxed ceramic powder material in to a predetermined shape;flux sintering the shaped fluxed ceramic powder; and forming a denselithium conducting material, the dense lithium conducting material beingcharacterized by a second density, the second density is at least 20%higher than the first density.
 26. The method of claim 25 fcomprising:mixing at least the first flux material and the second flux material toform a eutectic mixture, the eutectic mixture being characterized by amelting point of less than 800° C.; subjecting the eutectic mixture to atemperature of about 100 to 1000° C.
 27. A method for depositing lithiumgarnet material, the method comprising: providing components of lithiumconducting ceramic powder material at a first quantity, the componentsbeing characterized by a first density, the components beingcharacterized by a median particle size of about 100 nm to 10 μm;providing a first flux material at a second quantity, the first quantitybeing more than 100% of the second fquantity, the first flux materialcomprising inorganic salts of lithium material, the first flux materialbeing characterized by a melting temperature of about 500-1000° C.;providing a second flux material at a third quantity, the second fluxmaterial being characterized by a melting temperature of about 500-1000°C.; mixing the first flux material and the second flux material with thecomponents to form the fluxed ceramic powder material; shaping thefluxed ceramic powder material into a predetermined shape; fluxsintering the shaped fluxed ceramic powder material; and forming a denselithium conducting material, the dense lithium conducting material beingcharacterized by a second density, the second density is at least 20%higher than the first density.